US6911083B2

Method for producing powders made of gallium nitride and apparatus for producing the same

Summary by NHIP

Separate Reactor GaN Powder Production

The method produces gallium nitride powders by growing crystals from nuclei via reaction with gallium halide and ammonia gas. Distinctive elements include performing the creation and growth steps in independently provided reactors where the halide forms from a gallium melt and hydrogen halide in a pre-reactor.

Claim Score by NHIP

Read claim 1, the broadest

Abstract

In a creation section of GaN crystal nuclei, a gallium vapor and an ammonia gas are chemically reacted to create GaN crystal nuclei, which are transported into a growth section of GaN powders with a nitrogen carrier gas. In the growth section of GaN powders, a gallium chloride created in a pre-reactor is chemically reacted with the ammonia gas transported from the creation section of GaN crystal nuclei on the GaN crystal nuclei, to produce GaN powders through the crystal growth.

US6911083B2, drawing sheet 1 — Sheet 1 of 6

Term

Term ended

Expired 24 March 2023, 3.5 years ago.

16 claims: 1 independent, 15 dependent

1
Broadest claimClaim Score 58, broad(NHIP)A method for producing powders made of gallium nitride, comprising:a creation step of crystal nuclei wherein crystal nuclei made of gallium nitride are created, and a growth step of powders wherein crystals made of gallium nitride are grown from said crystal nuclei of gallium nitride through a chemical reaction between a gallium halide and an ammonia gas on said crystal nuclei of gallium nitride, to produce said gallium nitride powders, said growth step of powders being continued from said creation step of crystal nuclei in period of time, said growth step being separated from said creation step of crystal nuclei.

64 paragraphs in 5 sections, as filed

BACKGROUND OF THE INVENTION

00011. Field of the Invention

0002This invention relates to a method for producing gallium nitride powders and an apparatus for producing the gallium nitride powders which are preferably employed as fluorescent powders to make an optical display.

00032. Description of the Prior Art

0004Recently, a short wavelength semiconductor laser and a light-emitting diode which utilize excellent light emission performance of GaN-based III nitride semiconductor come into practical use, and also, an optical display which utilizes fluorescent properties of GaN is developed.

0005In the application of GaN for the optical display, it is required to prepare GaN powders, which can be made by following the technique, for example, disclosed in Japanese Patent Application Laid-open 2000-198978 where ammonia solution is dropped in gallium nitric hydrate solution to form gallium hydroxide, and then, obtain porous gallium oxide through moisture elimination, which is heated under ammonia atmosphere to obtain the GaN powders.

0006Moreover, the GaN powders can be made by means of the technique disclosed in J. American Ceramic Society, 79, 2309-2312 (1996) where metallic gallium is heated within a temperature range of 900-1000° C. and melted to form gallium melt, which is chemically reacted with ammonia gas to obtain the GaN powders.

0007In a conventional producing method of GaN powders as mentioned above, however, it takes long time of several hours to several days in batch process, so the production efficiency is extremely low and the mass production can not be realized. As of now, therefore, a practically usable producing method and apparatus of GaN powders can not be provided.

SUMMERY OF THE INVENTION

0008It is an object of the present invention to provide a producing method of GaN powders which is practically usable and can realize the mass production, and an apparatus for producing the GaN powders.

0009In order to achieve the above object, this invention relates to a method for producing powders made of gallium nitride, comprising:

0010a creation step of crystal nuclei wherein crystal nuclei made of gallium nitride are created, and

0011a growth step of powders wherein crystals made of gallium nitride are grown from the crystal nuclei of gallium nitride through a chemical reaction between a gallium halide and an ammonia gas on the crystal nuclei of gallium nitride, to produce the gallium nitride powders,

0012the growth step of powders being continued from the creation step of crystal nuclei in period of time.

0013The Inventor had intensely studied to develop a producing method of GaN powders which can be applied for the mass production of GaN powders through the production in short time of period. As a result, the inventor employed two continuous production steps for the GaN powders instead of a conventional one production step, so produced a large amount of GaN powders in short period of time.

0014As is described in Japanese Patent Application Tokukai Hei 10-373540, in a conventional producing method, the GaN powders are produced directly from the porous gallium oxide through one production step. In contrast, in the present invention, GaN crystal nuclei are grown in the first production step, and gallium halide and ammonia gas are reacted on the GaN crystal nuclei to produce the GaN powders in the second production step.

0015In the present invention, although the multi-production steps are employed for producing the GaN powders as mentioned above, the total production period of time can be sufficiently shortened because the reaction period of each step is extremely short and the two production steps are carried out continuously in period of time. Therefore, the producing method of the present invention can be employed for the mass production of GaN powders.

0016In the present invention, the creation step of crystal nuclei and the growth step of powders can be independently carried out in their respective reactors. In this case, the operationalities of the crystal nuclei creation step and the powder growth step can be developed, and thus, parameters in the steps can be easily controlled.

0017A producing apparatus of GaN powders according to the present invention comprises:

0018a creating means of crystal nuclei to create crystal nuclei made of gallium nitride, and

0019a growing means of powders to grow crystals made of gallium nitride from said crystal nuclei of gallium nitride through a chemical reaction between a gallium halide and an ammonia gas on said crystal nuclei of gallium nitride, to produce said gallium nitride powders.

BRIEF DESCRIPTION OF THE DRAWINGS

0020For better understanding of the present invention, reference is made to the attached drawings, wherein

0021<figref idref="DRAWINGS">FIG. 1</figref> is a structural view schematically showing an producing apparatus preferably to be employed in producing GaN powders according to the present invention,

0022<figref idref="DRAWINGS">FIG. 2</figref> is another structural view schematically showing an producing apparatus preferably to be employed in producing GaN powders according to the present invention,

0023<figref idref="DRAWINGS">FIG. 3</figref> is a graph showing the relation between the average diameter of GaN powders and the Ga supply rate in a producing method of GaN powders according to the present invention,

0024<figref idref="DRAWINGS">FIG. 4</figref> is a graph showing X-ray diffraction spectra of GaN powders obtained by a producing method of GaN powders according to the present invention, and

0025<figref idref="DRAWINGS">FIG. 5</figref> is a graph showing the relation between the average diameter of GaN powders and the hydrogen halide gas supply rate in a producing method of GaN powders according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

0026This invention will be described in detail with reference to the accompanying drawings. <figref idref="DRAWINGS">FIG. 1</figref> is a structural view schematically showing an producing apparatus preferably to be employed in producing GaN powders according to the present invention. A producing apparatus of GaN powders illustrated in <figref idref="DRAWINGS">FIG. 1</figref> is composed of two continuous reactors, one of which is classified in a creation section 10 of GaN crystal nuclei and the other of which is classified in a growth section 30 of GaN powders.

0027The creation section 10 includes a reactor 1 and cylindrical electric furnaces 2 and 3 provided on the periphery of the reactor 1. Then, a crucible 4 made of e.g., BN is provided in the lower side of the reactor 1 and a coil 5 for heating is provided so as to whirl around the crucible 4. Moreover, gas inlets 6 and 7 are provided in the lower side of the reactor 1.

0028The growth section 30 includes a reactor 11 and cylindrical electric furnaces 12-15 provided on the periphery of the reactor 11. In the reactor 11 is provided a pre-reactor 21 where a crucible 16 made of e.g., BN is provided and in the upper side of which gas inlets 17-19 are provided. Also, in the lower side of the reactor 11 are provided a filter 25 and a gas outlet 26.

0029The creation section 10 of GaN crystal nuclei and the growth section 30 of GaN powders are joined with a given cylindrical member 20.

0030In the producing method of GaN powders of the present invention, first of all, GaN crystal nuclei are created in the creation section 10. A metallic gallium raw material is prepared in the crucible 4, and then, heated at 1400° C. or over to create a gallium vapor. Then, an ammonia gas is introduced with a nitrogen carrier gas into the reactor 1 from the gas inlet 6 and a nitrogen carrier gas is introduced into the reactor 1 from the gas inlet 7 to chemically react the ammonia gas and the gallium vapor and thus, to create GaN crystal nuclei.

0031The reaction temperature of the ammonia gas and the gallium vapor is not particularly restricted, but preferably set within 1050-1100° C. by controlling the furnaces 2 and 3. In this case, the crystallinity of the GaN crystal nuclei can be much enhanced.

0032The wording “gallium vapor” means a perfectly gasified vapor and a vapor including minute liquid droplets. It is not required to create the GaN crystal nuclei through the chemical reaction between the gallium vapor and the ammonia gas as mentioned above. The GaN crystal nuclei may be created by another means.

0033Then, the resultant GaN crystal nuclei are transported into the growth section 30 of GaN powders through the cylindrical member 20 by utilizing e.g., the nitrogen carrier gas.

0034In the growth section 30, metallic gallium grains are charged into the crucible 16 in the pre-reactor 21, and then, heated to form a gallium melt. Then, a hydrogen halide gas is introduced with a nitrogen carrier gas into the pre-reactor 21 from the gas inlet 18, and a nitrogen carrier gas is also introduced into the pre-reactor 21 from the gas inlet 17. Then, the resultant gallium melt is chemically reacted with the hydrogen halide gas to create a gallium halide raw material gas. The resultant gallium halide raw material gas is transported downward into the reactor 11 with the above nitrogen carrier gas.

0035Into the reactor 11 are transported the GaN crystal nuclei and the ammonia gas from the creation section 10 and is introduced a nitrogen carrier gas from the gas inlet 19. Therefore, the gallium halide raw material gas is chemically reacted with the ammonia gas on the GaN crystal nuclei to obtain desired GaN powders through the crystal growth of GaN on the GaN crystal nuclei.

0036The resultant GaN powders are transported downward, and selected and collected with the filter 25. The remnant ammonia gas and hydrogen halide gas and a NH4Cl gas as a by-product produced through the chemical reaction between the raw material gases are discharged outside from the gas outlet 26.

0037The crystal growth of GaN on the GaN crystal nuclei is preferably carried out within 900-1100° C. by appropriately controlling the furnaces 12-14. In this case, the crystallinity of the GaN powders can be enhanced.

0038The furnace 15 is employed to heat the filter 25 so as to prevent the stack of by-product from NH4Cl gas through vaporization. In this point of view, the area around the filter 25 is heated at about 500° C. with the furnace 15.

0039In the producing apparatus shown in <figref idref="DRAWINGS">FIG. 1</figref>, the gallium melt is chemically reacted with the hydrogen halide in the pre-reactor 21 to form the gallium halide raw material gas to be used in the powder growth of GaN. Without the pre-reactor 21, however, the gallium halide raw material gas may be introduced into the reactor 11 directly from the outside.

0040It is desired, however, as mentioned above, that a hydrogen halide is directly introduced into a reactor where the powder growth of GaN is carried out, and then, a gallium halide raw material gas is directly created in the reactor. In this case, the remnant gallium vapor not chemically reacted with the ammonia gas in the creation section 10 of GaN crystal nuclei is transported into the growth section 30 of GaN powders with the nitrogen carrier gas, and then, can be chemically reacted with the hydrogen halide. Therefore, the yield of GaN powders can be enhanced.

0041Gallium chloride and gallium bromide may be exemplified as the gallium halide. In view of reactivity and availability, the gallium chloride may be preferably employed.

0042<figref idref="DRAWINGS">FIG. 2</figref> is another structural view schematically showing an producing apparatus preferably to be employed in producing GaN powders according to the present invention. Like constituent elements are designated by like reference numerals throughout.

0043A producing apparatus of GaN powders illustrated in <figref idref="DRAWINGS">FIG. 2</figref> is also composed of two continuous reactors as the one illustrated in <figref idref="DRAWINGS">FIG. 1</figref>, one of which is classified in a creation section 10 of GaN crystal nuclei and the other of which is classified in a growth section 30 of GaN powders. The creation section 10 includes a reactor 1 and cylindrical electric furnaces 2 and 3 provided on the periphery of the reactor 1. Then, a crucible 4 made of e.g., BN is provided in the lower side of the reactor 1 and a coil 5 for heating is provided so as to whirl around the crucible 4. Moreover, gas inlets 6 and 7 are provided in the lower side of the reactor 1.

0044The growth section 30 includes a reactor 11 and cylindrical electric furnaces 12-15 provided on the periphery of the reactor 11. In the reactor 11 is provided a pre-reactor 21 where a crucible 16 made of e.g., BN is provided and in the upper side of which a gas inlet 18 is provided. Also, in the upper side of the reactor 11 is provided a gas inlet 19. Moreover, in the lower side of the reactor 11 are provided a filter 25 and a gas outlet 26.

0045The creation section 10 of GaN crystal nuclei and the growth section 30 of GaN powders are joined with a given cylindrical member 20.

0046In the producing apparatus shown in <figref idref="DRAWINGS">FIG. 2</figref>, too, GaN crystal nuclei are created in the creation section 10 as in the producing apparatus shown in FIG. 1. Herein, however, an ammonia gas is introduced into the reactor 1 from the gas inlet 6, and a nitrogen carrier gas is introduced into the reactor 1 from the gas inlet 7. The resultant GaN crystal nuclei are transported into the growth section 30 with the above nitrogen carrier gas through the cylindrical member 20.

0047In the growth section 30 of the producing apparatus shown in <figref idref="DRAWINGS">FIG. 2</figref>, GaN powders are produced on the producing steps as described with reference to the producing apparatus shown in <figref idref="DRAWINGS">FIG. 1</figref> fundamentally. That is, a gallium melt created by heating a metallic gallium raw material in the crucible 16 provided in the pre-reactor 21 is chemically reacted with a hydrogen halide introduced from the gas inlet 18 to form a gallium halide raw material gas. Then, the gallium halide raw material gas is chemically reacted with the ammonia gas on the GaN crystal nuclei which are transported from the creation section 10, to produce GaN powders through the crystal growth of GaN on the GaN nuclei.

0048In the producing apparatus shown in <figref idref="DRAWINGS">FIG. 2</figref>, however, a nitrogen gas is flowed in the space between the pre-reactor 21 and the reactor 11. In this case, the GaN powder yield can be much enhanced, as compared with the producing apparatus shown in FIG. 1. Therefore, the producing ratio of GaN powders can be much increased. In addition, the stack of GaN debris on the inner wall of the reactor 11 can be effectively prevented, so that the maintenance for the producing apparatus can be mitigated.

0049Herein, the gallium halide raw material gas may be introduced from the outside of the reactor 11 instead of employing the pre-reactor 21, as mentioned above. In this case, the nitrogen gas is flowed along the inner wall of the reactor 11. Another non-active gas such as hydrogen gas may be employed, in addition to the nitrogen gas.

0050The resultant GaN powders are transported downward with the above nitrogen carrier gas, and then, selected and collected with the filter 25. The remnant ammonia gas and hydrogen halide gas and a NH4Cl gas as a by-product through the chemical reaction between the raw material gases are discharged outside from the gas outlet 26. The area around the filter 25 is heated at about 500° C. with the furnace 15 so as to prevent the stack of by-product from NH4Cl gas through vaporization.

0051The crystal growth of GaN on the GaN crystal nuclei is preferably carried out within 900-1100° C. by appropriately controlling the furnaces 12-14. In this case, the crystallinity of the GaN powders can be enhanced. Other conditions for the producing apparatus may be employed as in the producing apparatus shown in FIG. 1.

EXAMPLES

Example 1

0052In this Example, GaN powders were produced continuously by utilizing the producing apparatus shown in FIG. 1. The reaction temperature in the creation section 10 of GaN crystal nuclei was set to 1100° C., and the reaction temperature in the growth section 30 of GaN powders was set to 900 C, 1000° C., or 1100° C.

0053The supply rate of ammonia gas from the gas inlet 6 in the creation section 10 was set to 500 sccm, and the supply rate of nitrogen carrier gas from the gas inlet 6 was set to 500 sccm. The supply rate of nitrogen carrier gas from the gas inlet 7 was set to 3000 sccm. The supply rate of nitrogen carrier gas from the gas inlet 17 in the growth section 30 was set to 500 sccm, and the supply rate of the hydrogen chloride gas from the gas inlet 18 was set to 8 sccm. The supply rate of nitrogen carrier gas from the gas inlet 18 was set to 500 sccm, and the supply rate of nitrogen carrier gas from the gas inlet 19 was set to 500 sccm.

0054<figref idref="DRAWINGS">FIG. 3</figref> is a graph showing the relation between the average diameter of the resultant GaN powders and the Ga supply rate (g/hr). As is apparent from <figref idref="DRAWINGS">FIG. 3</figref>, the average diameter of GaN powders is increased as the Ga supply rate is increased. In this Example, the GaN powders are grown sufficiently enough to have a large average diameter practically usable, so it is confirmed that the GaN powders practically usable can be obtained according to the present invention. Therefore, the producing period of time can be shortened, and thus, it is turned out that the producing method of the present invention is practically usable.

0055In this Example, the yield of GaN powders was 10%, and the producing rate of GaN powders was 0.04 g/hr.

0056<figref idref="DRAWINGS">FIG. 4</figref> is a graph showing X-ray diffraction spectra of the GaN powders produced at 900° C., 1000° C. and 1100° C., respectively. As is apparent from <figref idref="DRAWINGS">FIG. 4</figref>, diffraction peaks from GaN crystal appear within a range of 2θ=30-70 degrees. Therefore, it is turned out that the crystallinity of the GaN powders is excellent.

Example 2

0057In this Example, GaN powders were produced continuously by utilizing the producing apparatus shown in FIG. 2. The reaction temperature in the creation section 10 of GaN crystal nuclei was set to 1100° C., and the reaction temperature in the growth section 30 of GaN powders was set to 900° C., 1000° C., or 1100° C.

0058The supply rate of ammonia gas from the gas inlet 6 in the creation section 10 was set to 500 sccm, and the supply rate of nitrogen carrier gas from the gas inlet 7 was set to 1000 sccm. The supply rate of the hydrogen chloride gas from the gas inlet 18 in the growth section 30 was set within 2-15 sccm, and the supply rate of nitrogen carrier gas from the gas inlet 18 was set within 25-60 sccm. The supply rate of nitrogen carrier gas from the gas inlet 19 was set to 3800 sccm.

0059<figref idref="DRAWINGS">FIG. 5</figref> is a graph showing the relation between the average diameter of the resultant GaN powders and the hydrogen chloride gas supply rate. As is apparent from <figref idref="DRAWINGS">FIG. 5</figref>, the average diameter of the GaN powders is increased as the hydrogen chloride gas supply rate is increased. Therefore, it is turned out that the GaN powders are produced through the powder growth on the GaN crystal nuclei.

0060In this Example, the yield of GaN powders was 25%, and the producing rate of GaN powders was 0.14 g/hr. It is turned out, therefore, that if the producing apparatus shown in <figref idref="DRAWINGS">FIG. 2</figref> is employed, the yield and the producing rate of the resultant GaN powders can be enhanced, compared with the one shown in FIG. 1.

0061Although the present invention was described in detail with reference to the above examples, this invention is not limited to the above disclosure and every kind of variation and modification may be made without departing from the scope of the present invention. For example, in the above embodiments, two independent reactors are prepared, and the creation step of crystal nuclei and the growth step of powders are carried out in the respective reactors, independently. If an open tube-type reactor is prepared, however, the creation step and the growth step can be carried out in the single reactor at a time.

0062According to the producing method and the producing apparatus of the present invention, GaN powders can be produced continuously. Therefore, the producing period of time of GaN powders can be extremely shortened, and thus, the mass production of GaN powders can be realized, which is different from a conventional batch-type producing method.

Contents5

Every citation, both ways

Citations
Document	Relation	Office	Cited during
WO2008064083A3	Cited by	World Intellectual Property Organization (WIPO)	International search
US9481944B2	Cited by	United States of America	Applicant
US7935382B2	Cited by	United States of America	Search report
US8887650B2	Cited by	United States of America	Applicant
US8323407B2	Cited by	United States of America	Applicant
US9038565B2	Cited by	United States of America	Applicant
US2009178611A1	Cited by	United States of America	Pre-grant
US8382898B2	Cited by	United States of America	Applicant
US8486192B2	Cited by	United States of America	Applicant
US8785316B2	Cited by	United States of America	Applicant
US8197597B2	Cited by	United States of America	Applicant
US2009223453A1	Cited by	United States of America	Pre-grant
US9580836B2	Cited by	United States of America	Applicant
WO2008064083A2	Cited by	World Intellectual Property Organization (WIPO)	International search
US9481943B2	Cited by	United States of America	Applicant
US7718002B2	Cited by	United States of America	Search report
US8545628B2	Cited by	United States of America	Applicant
US2009205563A1	Cited by	United States of America	Pre-grant
US2009223441A1	Cited by	United States of America	Pre-grant
US8133806B1	Cited by	United States of America	Applicant
US8486193B2	Cited by	United States of America	Applicant
US2009283029A1	Cited by	United States of America	Pre-grant
US8585820B2	Cited by	United States of America	Applicant
US2007141819A1	Cited by	United States of America	Pre-grant
US2008216737A1	Cited by	United States of America	Pre-grant
JP2000198978A	Cites	Japan	Applicant
JP2001151504A	Cites	Japan	Applicant
US2002158267A1	Cites	United States of America	Search report
US2003012874A1	Cites	United States of America	Search report
US2003183155A1	Cites	United States of America	Search report
US2003209191A1	Cites	United States of America	Search report
US4144116A	Cites	United States of America	Search report
US5294565A	Cites	United States of America	Search report
US6096282A	Cites	United States of America	Search report
US6120748A	Cites	United States of America	Search report
US6139628A	Cites	United States of America	Search report
US6177057B1	Cites	United States of America	Search report
US6406677B1	Cites	United States of America	Search report

5 priority claims, no other members on record

This recordMember, by publication datePriority claim

Priority claims5

Priority claims
Document	Office	Kind	Date
2002169784	Japan	–	2002-06-11
2002169784	Japan	A	2002-06-11
2002169784	Japan	A	2002-06-11
2002169784	–	–	–
JP20020169784	–	–	–

42 transactions on the USPTO file

Allowed after 1 non-final rejection.

Non-final rejections: 1
Final rejections: 0
RCEs: 0
Appeals: 0

Over time

Point at a mark for the transaction

Transactions

Prosecution transactions, newest first
	Event
2009-07-27	Expire Patent
2005-06-28	Recordation of Patent Grant Mailed
2005-06-28	Patent Issue Date Used in PTA CalculationAllowed
2005-06-08	Issue Notification MailedAllowed
2005-06-03	Receipt into Pubs
2005-06-03	Dispatch to FDC
2005-06-03	Application Is Considered Ready for Issue
2005-04-28	Issue Fee Payment Verified
2005-04-28	Issue Fee Payment Received
2005-03-28	Workflow - File Sent to Contractor
2005-02-24	Mail Notice of AllowanceAllowed
2005-02-24	Mail Examiner's Amendment
2005-02-23	Notice of Allowance Data Verification CompletedAllowed
2005-02-23	Case Docketed to Examiner in GAU
2005-02-22	Examiner's Amendment Communication
2005-01-27	Mail Examiner Interview Summary (PTOL - 413)
2005-01-25	Interview Summary Record
2004-11-30	Information Disclosure Statement (IDS) Filed
2004-11-30	Information Disclosure Statement (IDS) Filed
2004-10-14	Date Forwarded to Examiner
2004-09-29	Response after Non-Final Action
2004-09-29	Workflow incoming amendment IFW
2004-06-29	Mail Non-Final RejectionNon-final rejection
2004-06-25	Non-Final RejectionNon-final rejection
2004-06-03	Workflow incoming amendment IFW
2003-12-04	Request for Foreign Priority (Priority Papers May Be Included)
2003-12-04	Request for Foreign Priority (Priority Papers May Be Included)
2003-09-10	IFW TSS Processing by Tech Center Complete
2003-09-10	IFW TSS Processing by Tech Center Complete
2003-08-14	Case Docketed to Examiner in GAU
2002-11-25	Case Docketed to Examiner in GAU
2002-11-05	Application Dispatched from OIPE
2002-11-04	Application Is Now Complete
2002-10-22	Information Disclosure Statement (IDS) Filed
2002-10-22	Information Disclosure Statement (IDS) Filed
2002-10-22	Preliminary Amendment
2002-10-22	Additional Application Filing Fees
2002-10-22	A statement by one or more inventors satisfying the requirement under 35 USC 115, Oath of the Applic
2002-08-27	Notice Mailed--Application Incomplete--Filing Date Assigned
2002-08-13	IFW Scan & PACR Auto Security Review
2002-08-12	IFW Scan & PACR Auto Security Review
2002-07-30	Initial Exam Team nn

5 legal events, as the office reported them to INPADOC

Over the term

Point at a mark for the event

Events

Legal events, newest first
	Event	Code
2009-08-18	Lapsed due to failure to pay maintenance feeLapsedFP	FP
2009-07-27	Information on status: patent discontinuationPATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362STCH	STCH
2009-06-28	Lapse for failure to pay maintenance feesLapsedLAPS	LAPS
2009-01-05	Maintenance fee reminder mailedREMI	REMI
2002-10-22	AssignmentAS	AS